src/java.desktop/share/classes/com/sun/imageio/plugins/jpeg/JPEGImageWriter.java

*** 1,7 ****
  /*
!  * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
*** 301,310 ****
--- 301,318 ----
  
      public int getNumThumbnailsSupported(ImageTypeSpecifier imageType,
                                           ImageWriteParam param,
                                           IIOMetadata streamMetadata,
                                           IIOMetadata imageMetadata) {
+         // Check whether sufficient data is available.
+         if (imageType == null && imageMetadata == null) {
+             // The method has been invoked with insufficient data. Henceforth
+             // we return -1 as recommended by ImageWriter specification.
+             return -1;
+         }
+ 
+         // Check if the image type and metadata are JFIF compatible.
          if (jfifOK(imageType, param, streamMetadata, imageMetadata)) {
              return Integer.MAX_VALUE;
          }
          return 0;
      }